Problems faced by agricultural communities in the region include

The problems are the overgrazing, salinization(Soil salinity) and water availability. These are included to be the problems of agriculturists in the region

The agricultural problems that they face is overgrazing, salinization, and water availability.

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.